This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-276825, filed Sep. 29, 1999, the entire contents of which are incorporated herein by reference.
This invention relates to a door mechanism for opening and closing a card slot into which a PC card, for example, is inserted, and more particularly to a spring structure urging first and second door panels of the mechanism toward their closed positions.
An electronic apparatus such as a portable computer incorporates a card receptacle for receiving, for example, a PC card. This type of card receptacle has a card slot, which opens to a side surface of the computer. A door mechanism of a shutter type is provided at the card slot for preventing dust, foreign matter, etc. from getting into the card receptacle while a PC card is removed therefrom.
FIGS. 22 to 26 show an example of a conventional door mechanism 1. The door mechanism 1 includes a frame 2 and first and second door panels 3 and 4. The frame 2 has upper and lower walls 5a and 5b and left and right side walls 5c and 5d. The upper and lower walls 5a and 5b extend horizontal and parallel to each other. The side walls 5c and 5d extend vertical and connect the opposed ends of the upper and lower walls 5a and 5b. The walls 5a-5d are joined to form a slim insertion port 6. The insertion port 6 functions as a card slot for inserting and ejecting a PC card 16.
First and second bearings 7a and 7b are formed at front edge portions of the side wall 5c. The first and second bearings 7a and 7b are vertically separated from each other. A third bearing 7c is formed at a front edge portion of the upper wall 5a. The third bearing 7c is opposed to the first bearing 7a at the upper edge of the insertion port 6. A fourth bearing 7d is formed at a front edge portion of the lower wall 5b. The fourth bearing 7d is situated below the third bearing 7c, and opposed to the second bearing 7b at the lower edge of the insertion port 6.
As is shown in FIG. 24, the first to fourth bearings 7a-7d have bearing holes 8a-8d, respectively. The bearing hole 8a of the first bearing 7a is arranged coaxial with the bearing hole 8c of the third bearing 7c, with the insertion port 6 interposed therebetween. The bearing hole 8b of the second bearing 7b is arranged coaxial with the bearing hole 8d of the fourth bearing 7d, with the insertion port 6 interposed therebetween.
The first and second door panels 3 and 4 are made of an elastically deformable synthetic resin, and formed of slim plate-like members extending along the insertion port 6. The first and second door panels 3 and 4 are arranged vertical inside the insertion port 6.
The first door panel 3 is situated between the first and third bearings 7a and 7c, and has first and second end portions separated from each other along the length of the insertion port 6. The first end portion has a first pivot shaft 10a projecting to the first bearing 7a, while the second end portion has a second pivot shaft 10b projecting to the third bearing 7c. The first pivot shaft 10a is fitted in the bearing hole 8a of the first bearing 7a such that it can pivot axially. The second pivot shaft 10b is fitted in the bearing hole 8c of the third bearing 7c such that it can pivot axially. Thus, the first door panel 3 is supported by the frame 2 such that it can pivot on the first and second pivot shafts 10a and 10b between a closed position in which the upper half space of the insertion port 6 is closed, and an open position in which the upper half space of the insertion port 6 is open.
The second door panel 4 is situated between the second and fourth bearings 7b and 7d, and has first and second end portions separated from each other along the length of the insertion port 6. The first end portion has a first pivot shaft 11a projecting to the second bearing 7b, while the second end portion has a second pivot shaft 11b projecting to the fourth bearing 7d. The first pivot shaft 11a is fitted in the bearing hole 8b of the second bearing 7b such that it can pivot axially. The second pivot shaft 11b is fitted in the bearing hole 8d of the fourth bearing 7d such that it can pivot axially. Thus, the second door panel 4 is supported by the frame 2 such that it can pivot on the first and second pivot shafts 11a and 11b between a closed position in which the lower half space of the insertion port 6 is closed, and an open position in which the lower half space of the insertion port 6 is open.
As is shown in FIG. 22 or 25, where the first and second door panels 3 and 4 are in their closed positions, they stand straight, are situated in a single vertical plane, and appear in the insertion port 6. On the other hand, where the first and second door panels 3 and 4 are in their open positions, they are folded substantially horizontally along the upper and lower walls 5a and 5b of the frame 2, and are retreated from the insertion port 6.
The first and second bearings 7a and 7b each have a stopper 12. The stoppers 12 are brought into contact with the first and second door panels 3 and 4 when the panels are swung from their open positions to their closed positions, thereby limiting an excessive movement thereof.
The first and second door panels 3 and 4 are urged toward their closed positions by means of respective helical torsion springs 13. As shown in FIG. 26 or 27, each helical torsion spring 13 has a coil section 14, a first arm section 15a and a second arm section 15b. The coil section 14 is formed by tightly winding a metal strand. The first arm section 15a radially extends from an end of the coil section 14. The second arm section 15b tangentially extends from the other end of the coil section 14. When the helical torsion spring 13 is viewed from a direction along the axis of the coil section 14, as is shown in FIG. 25, the first and second arm sections 15a and 15b extend in different circumferential directions of the coil section 14. The angle-of-twist xcex8 of the helical torsion spring 13, determined by the arm sections 15a and 15b, is set at about 100xc2x0 or more when the spring 13 is in a free state in which no load is applied thereto.
The first and second door panels 3 and 4 are designed to pivot in opposite directions. Accordingly, the helical torsion springs 13 incorporated in the first and second door panels 3 and 4 have windings wound in opposite directions.
More specifically, as shown in FIG. 24, in the first door panel 3, the coil section 14 of the helical torsion spring 13 is mounted on the circumference of the first pivot shaft 10a. The coil section 14 is mounted on the pivot shaft 10a such that first arm section 15a extends downward from the shaft 10a in contact with the reverse surface of the first door panel 3. Further, the second arm section 15b extends from the first pivot shaft 10a in a direction perpendicular to the first door panel 3, and has its tip hooked on the upper wall 5a of the frame 2.
In the second door panel 4, the coil section 14 of the helical torsion spring 13 is mounted on the circumference of the second pivot shaft 11b. The coil section 14 is mounted on the pivot shaft 11b such that first arm section 15a extends upward from the shaft 11b in contact with the reverse surface of the second door panel 4. Further, the second arm section 15b extends from the second pivot shaft 11b in a direction perpendicular to the second door panel 4, and has its tip hooked on the lower wall 5b of the frame 2.
Where the helical torsion springs 13 are incorporated in the first and second door panels 3 and 4 as shown in FIGS. 23 to 26, each first arm section 15a is urged in a direction in which the coil section 14 is tightened. In this state, the angle-of-twist xcex8 determined by the arm sections 15a and 15b is reduced. Accordingly, each coil section 14 generates a repulsive force to return the corresponding first arm section 15a to its original position, thereby swinging the first and second door panels 3 and 4 until they are brought into contact with the stoppers 12. As a result, the first and second door panels 3 and 4 are kept in their closed positions.
When the first and second door panels 3 and 4 have been swung from their closed positions to their open positions, the first arm sections 15a are urged more than before, and hence the angle-of-twist xcex8 becomes a value close to 0, thereby increasing the repulsive forces of the coil sections 14. These increased repulsive forces serve as restoring forces for restoring the door panels 3 and 4 from the open positions to the closed positions.
When the PC card 16 is not inserted in the card receptacle, the first and second door panels 3 and 4 are kept in their closed positions as shown in FIG. 22 or 25. When the front end of the PC card 16 has been urged against the first door panel 3 to insert it into an upper stage of the card receptacle, the first door panel 3 is swung against the repulsive force of the helical torsion spring 13, and retreated into the insertion port 6. Thus, the insertion port 6 is opened, through which the PC card 16 is pushed into the card receptacle. The first door panel 3 is kept in the open position by the PC card 16.
Further, when the PC card 16 has been taken out of the insertion port 6 by an ejecting operation, the first door panel 3 is automatically restored from the open position to the closed position by the repulsive force of the helical torsion spring 13. This means that the first door panel 3 automatically closes the insertion port 6.
In the door mechanism 1 constructed as above, the first and second door panels 3 and 4 are incorporated in the frame 2 with their respective helical torsion springs 13 mounted thereon.
The procedure of assembly of the first and second door panels 3 and 4 will be described with reference to the aforementioned figures and FIG. 28. First, the coil section 14 of the helical torsion spring 13 is mounted on the first pivot shaft 10a of the first door panel 3. Subsequently, while holding the coil section 14 with the fingertips to prevent it from rotating unintentionally, the first pivot shaft 10a is inserted into the bearing hole 8a of the first bearing 7a, so that the first arm section 15a will face the reverse surface of the first door panel 3. The insertion of the first pivot shaft 10a is executed with the first door panel 3 protruding in front of the corresponding stopper 12 of the frame 2, so that the frame 2 and the stoppers 12 will not interrupt the inserting operation.
After that, the first door panel 3 is pushed toward the side wall 5c, and is forcibly bent while taking care not to disengage the first pivot shaft 10a from the bearing hole 8a. By bending the panel 3, the distance between the first and second pivot shafts 10a and 10b is temporarily narrowed to thereby fit the second pivot shaft 10b in the bearing hole 8c of the third bearing 7c. 
Lastly, the first door panel 3 is pushed into the insertion port 6, and then forcibly swung so as to pass the stopper 12. As a result of the swinging operation, the first arm section 15a of the helical torsion spring 13 is caught on the reverse surface of the first door panel 3, and the second arm section 15b is caught on the upper wall 5a. Accordingly, the helical torsion spring 13 is mounted on the first pivot shaft 10a in a state in which it is tightened. The repulsive force of the spring 13 keeps the first door panel 3 in the closed position.
After finishing the assembly of the first door panel 3, the coil section 14 of another helical torsion spring 13 is mounted on the second pivot shaft 11b of the second door panel 4, thereby executing a procedure similar to the above to attach the second door panel 4 to the frame 2. Thus, the first and second door panels 3 and 4 are swingably attached to the frame 2 by repeating the same operation twice.
As described above, in the conventional door mechanism 1, the helical torsion springs 13 that urge the first and second door panels 3 and 4 toward their closed positions are manually attached to the first and second pivot shafts 10a and 11b of the first and second door panels 3 and 4, respectively.
In the manual attachment, the first and second door panels 3 and 4 are designed to pivot in opposite directions, and therefore the helical torsion springs 13 must be attached to the panels 3 and 4 in opposite directions. This being so, when mounting the helical torsion springs 13 onto the first and second pivot shafts 10a and 11b of the first and second door panels 3 and 4, it is necessary to execute assemblage while taking great care of the winding directions of the first and second arm sections 15a and 15b of each helical torsion spring 13. This inevitably reduces the efficiency of assemblage, and time and effort are required for the assemblage of the first and second door panels 3 and 4 including the helical torsion springs 13.
Moreover, the helical torsion spring 13 is an extremely small member. Therefore, even if the helical torsion springs 13 are mounted on the first and second pivot shafts 10a and 11b in wrong directions, it is very possible that this will not be known and will interrupt the assemblage.
In addition, since the helical torsion spring 13 is very small, great care must be taken when handling it, and/or a tool such as forceps must be required. Thus, time and effort are necessary in handling the helical torsion spring 13 itself. This also reduces the efficiency of assemblage.
Furthermore, since the helical torsion spring 13 has first and second arm sections 15a and 15b leading from the opposite ends of the coil section 14, if, in particular, multiple helical torsion springs are prepared in one place, they will easily be entangled. In such a case, complicated work, for example, separation of tangled springs by manual labor, may be required before attaching the helical torsion springs 13 to the first and second door panels 3 and 4. During such separation work, it is possible that the helical torsion springs 13 will spring apart, with the result that some will be lost or deformed.
Also, as described above, the coil sections 14 of the helical torsion springs 13 are mounted on the first and second pivot shafts 10a and 11b of the first and second door panels 3 and 4, and then the shafts 10a and 11b must be inserted into the bearing holes 8a and 8c while holding the coil sections 14 with the fingertips so as not to move them. If, at this time, the first and second pivot shafts 10a and 11b are disengaged from the bearing holes 8a and 8c, the assemblage must be again executed from the beginning. Further, it is possible that the helical torsion springs 13 will be dismounted from the first and second pivot shafts 10a and 11b and fly off because of their force of tension.
In summary, in the prior art, it is necessary to simultaneously execute both the operation of pressing the small helical torsion spring 13 with the fingertips so as to arrange the first and second arm sections 15a and 15b in correct directions, and the operation of inserting, into the bearing holes 8a and 8c, the first and second pivot shafts 10a and 11b with the helical torsion springs 13 mounted thereon. This requires concentration and/or skill, and is the greatest cause of degrading the efficiency of assemblage of the first and second door panels 3 and 4.
It is the object of the invention to provide a door mechanism in which springs for urging first and second door panels in their closed positions can be attached easily, thereby increasing the efficiency of assemblage of the first and second door panels.
According to an aspect of the invention, there is provided a door mechanism comprising: a frame having an insertion port; first and second door panels each having a pivot shaft connected to the frame such that the pivot shaft can rotate about an axis thereof, the first and second door panels being supported by the frame such that they can swing about the respective pivot shafts between closed positions in which the first and second door panels are situated in a single plane and close the insertion port, and open positions in which the first and second door panels open the insertion port, the first and second door panels being swung apart in opposite directions when they are shifted from the respective closed positions to the respective open positions; and a spring urging the first and second door panels toward the respective closed positions. The spring is characterized by including a first coil section mounted on the pivot shaft of the first door panel, a second coil section mounted on the pivot shaft of the second door panel, arm sections each extending from one end of a corresponding one of the first and second coil sections and urging the first and second door panels toward the respective closed positions, and a connecting section bridging another end of each of the first and second coil sections.
Since, in the above structure, the connecting section of the spring project around the first and second coil sections, it can be easily held with the fingertips. Moreover, the connecting section limits the rotation of the first and second coil sections, and hence the arm sections of the spring can be appropriately positioned with respect to the first and second door panels.
Therefore, the spring can be handled without any problem of deformation or loss thereof, and the efficiency of attaching the spring and the first and second door panels to the frame can be significantly improved.
Furthermore, in the above structure, the spring is a single structure that connects the first and second door panels. Accordingly, the number of the component parts of the door mechanism and the number of the processes of assembling the door mechanism can be reduced as compared with the conventional case where a helical torsion spring is necessary for each door panel.
According to another aspect of the invention, there is provided a door mechanism comprising: a frame having an insertion port and a plurality of bearings provided at edge portions of the insertion port; first and second door panels having respective pivot shafts supported by the bearings of the frame such that the pivot shafts can rotate about axes thereof, the first and second door panels being supported by the frame such that they can swing about the respective pivot shafts between closed positions in which the first and second door panels are situated in a single plane and close the insertion port, and open positions in which the first and second door panels open the insertion port, the first and second door panels being swung apart in opposite directions when they are shifted from the respective closed positions to the respective open positions; and a spring urging the first and second door panels toward the respective closed positions. The bearings of the frame have respective cylindrical hollow bosses in which the pivot shafts are inserted such that they can rotate about axes thereof. The spring is characterized by including first and second coil sections mounted on a circumference of the bosses, arm sections each extending from one end of a corresponding one of the first and second coil sections and urging the first and second door panels toward the respective closed positions, and a connecting section bridging another end of each of the first and second coil sections.
In the above structure, the first and second coil sections are mounted on the circumferences of the bosses formed at the bearings of the frame. Further, the first and second coil sections are connected by the connecting section, and hence the rotation of the first and second coil sections can be limited. This means that the arm sections of the spring can be appropriately positioned with respect to the first and second door panels.
Accordingly, the spring can be held on the frame before inserting the pivot shafts of the first and second door panels into the bearings of the frame. This enables individual execution of the positioning of the spring and the insertion of the pivot shafts. As a result, it is sufficient if the pivot shafts of the first and second door panels are inserted into the bosses on which the first and second coil sections are mounted. In other words, the above structure does not require the conventional complicated and troublesome operation of inserting the pivot shafts into the bearings while pressing the helical torsion springs with the fingertips.
Thus, the spring can be handled without any problem of deformation or loss thereof, and the efficiency of attaching the spring and the first and second door panels to the frame can be significantly improved.
Furthermore, in the above structure, the spring is a single structure that connects the first and second door panels. Accordingly, the number of the component parts of the door mechanism and the number of the processes of assembling the door mechanism can be reduced as compared with the conventional case where a helical torsion spring is necessary for each door panel.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.